1. Field of the Invention
The present invention relates to a heat exchanger equipped with partitioning members for use in a vehicular air conditioning apparatus mounted in a vehicle, for blowing air, which has been adjusted in temperature by the heat exchanger, into a vehicle compartment for thereby adjusting the temperature inside the vehicle compartment.
2. Description of the Related Art
In a vehicular air conditioning apparatus that is mounted in a vehicle, internal and external air is introduced into a casing by a blower, and after cooled air, which has been cooled by an evaporator that forms a cooling mechanism, and heated air, which has been heated by a heater core that forms a heating mechanism, are mixed together in the casing at a predetermined mixing ratio, the mixed air is blown out from a defroster blow-out port, a face blow-out port, or a foot blow-out port, whereby adjustment of temperature and humidity in the vehicle compartment is carried out.
With this type of vehicular air conditioning apparatus, for example, as disclosed in Japanese Laid-Open Patent Publication No. 05-178068, it is known to provide a first blower for the purpose of introducing vehicle compartment air into the casing, and a second blower for the purpose of introducing both internal air inside of the vehicle compartment and external air outside of the vehicle compartment into the casing. In such a vehicular air conditioning apparatus, air that is introduced from an internal air introduction port by rotation of the first blower is heated by a first heat exchanger and then is blown into the vehicle compartment through a first air passage from the face blow-out port or the foot blow-out port. In addition, air that is introduced from an external air introduction port by rotation of the second blower is heated by a second heat exchanger and then is blown into the vehicle compartment through a second air passage from the defroster blow-out port.
In the aforementioned vehicular air conditioning apparatus having the first and second air passages, for example, as disclosed in Japanese Laid-Open Patent Publication No. 10-278547, respective auxiliary partitioning plates are disposed on upstream and downstream sides of the heat exchanger, wherein by separating the first air passage and the second air passage by means of such auxiliary partitioning plates, air that flows through the first air passage and air that flows through the second air passage are separated from each other. On the other hand, the heat exchanger is formed in a thin box-like shape, and is constituted from a pair of tanks disposed on both ends thereof, a plurality of tubes interconnecting one and the other of the tanks, and fins which are disposed between the tubes. In the interior of the heat exchanger, directly above the auxiliary partition plates, plate members are inserted between the plural tubes, such that the interior of the heat exchanger is divided in half by the plate members, for thereby separating air that flows through the first air passage and air that flows through the second air passage. (See, for example, Japanese Laid-Open Patent Publication No. 10-278547.)
In this type of heat exchanger, it is known to provide a structure in which the tubes are arranged in two layers in the thickness direction of the heat exchanger. However, in the case that the plate members disclosed in Japanese Laid-Open Patent Publication No. 10-278547 are applied with respect to a heat exchanger having two layers of tubes, the plate members are inserted into the interior thereof from one side surface only of the heat exchanger, and since the region between one of the tubes and the other of the tubes cannot be sealed, leakage of air passing between the tubes cannot be prevented. Consequently, in such a heat exchanger having two layers of tubes formed in this manner, air that is separated by the auxiliary partitioning plates and flows into the heat exchanger through the first air passage and the second air passage flows in the interior of the heat exchanger from a passage side thereof having a large air-blowing rate and high pressure to a passage side thereof having a relatively small air-blowing rate and a low pressure. Therefore, a problem results in that the air inside each of the passages on the downstream side of the heat exchanger does not obtain a desired air-blowing rate, and ultimately, the mixing ratio between cool air and warm air changes, and along therewith, air which is blown out from respective blow-out ports inside the vehicle compartment fails to achieve the desired temperature and air-blowing rate.
Further, when the flow of air in either one of the first and second air passages is halted, air that flows through one of the passages tends to flow into the other passage while passing through the interior of the heat exchanger, and the air is blown out into the vehicle compartment. That is, blowing of air inside the vehicle compartment continues to be carried out unintentionally from blow-out ports for which blowing of air was intended to be halted, thus imparting a sense of discomfort to passengers in the vehicle.